The present invention relates to a furnace coiler for winding a strip to be rolled by a hot rolling mill, while keeping the strip hot or heating the strip.
In a conventional hot rolling system, a furnace coiler takes up a strip rolled by a hot rolling mill and heats the strip. As mentioned in, for example, U.S. Pat. No. 5,269,166 and Japanese Patent Laid-open Nos. Hei. 7-47422 and Hei. 8-332503, a furnace coiler, having a housing and a mandrel disposed in the housing, takes up a strip which moves on table rollers into the housing and around the mandrel to form a coil and heats the coil.
Internal devices of the furnace coiler, including the mandrel and strip guides, and the furnace walls of the furnace coiler are exposed to severe thermal conditions. Therefore, those internal devices and the furnace walls have short lifetimes and require frequent maintenance work. For example, the interior of the furnace coiler needs to be inspected nearly once every week for maintenance. However, the maintenance of the conventional furnace coiler is difficult. The conventional furnace coiler has a lower housing portion, and an upper housing portion fixed to the lower housing portion with bolts or the like, and the lower housing portion is provided with an inlet opening to receive a strip therethrough into the furnace coiler. As an example, a typical furnace coiler may be 4 m in diameter and 2 m in width, and the inlet opening is then as small as 2 m in width and only about 1 m in height. Therefore, it is impossible for a man to enter the housing for maintenance work. As a result, when removing the internal devices including the mandrel and the strip guides from the housing, the upper housing portion of the furnace coiler must be removed. Since the upper housing portion is a heavy structure of about 30 tons, it takes two days for four men to remove the upper housing portion from and reassemble the same with the lower housing portion.
Since, the housing is closed, except for the inlet opening, it takes a very long time of about 10 hours for the furnace coiler to cool down after the furnace coiler has been stopped.
Accordingly, the conventional furnace coiler has problems in that it requires difficult and frequent maintenance work, which reduces the yield and the productivity of the associated rolling system.
Accordingly, it is an object of the present invention to provide a furnace coiler which does not require difficult maintenance work and which is capable of improving the yield and the productivity of the associated rolling system.